OX66 issues stalling??

[mhff34]

I have twin 200,s that are both acting up since I got the boat out of storage. They lose rpm,s for a second and then run fine again. Usually happens when the boat slaps down hard or in rough water. Also not able to get past 44000rpms. Any advise would be appreciated. Thanks in advance

 

[Gary M]

Check/change the fuel/water filters.
Have O2 sensors serviced.
New plugs.
New fuel filters.
How old is the gas?
Have fuel pumps checked.

 

[Grog]

If the idle is fine and doesn't have power it sounds like the low pressure pumps (ethanol seems to kill them faster). Hopefully you changed the water separator at the begining of the year but if you haven't done the ones on the motors in a while do them too.

 

[dgreen1069]

This is most definitely a fuel related problem. The two most likely causes are your low pressure pumps or the Vapor Separator Tank filter. Both are diy fixes. The low pressure pumps are on the port side of the motor. They are each attached to the block with two screws. If you unscrew them, you can inspect them for any signs of gasoline....they should be completely dry. If they are leaking, fuel will most likely show itself on the back side of the pumps. If you don't see any fuel, pump your primer bulbs a few times.....if you don't see any fuel after that, they are probably OK. They are prone to fail, so it may be worth your while to replace them anyways....they are about $50 each.

The Vapor Separator Tank is the large metal tank sitting directly in front of the low pressure fuel pumps. It has about 10 screws on the top of it, and it is held on by 3 10mm bolts. If you remove all of the screws and take the top off, you will find the high pressure fuel pump. The pump has a screen filter that is prone to clogging. The filter can be cleaned once it is removed, but I went ahead and just replaced mine. My port engine had a surging issue, and fixing these two items made it run like new again.

 

[mhff34]

thanks for the replies! Is this something I can do with the boat in the water? Where is the best place to buy parts online or at a Grady dealer?

 

[fastal]

would not do the VST in the water if at all possible. as for parts I use baert marine, but in all honesty have never really shopped them against anybody for price, I also believe there is a very reputable yamaha supplier that has many refferals on here, SIM marine maybe???

 

[dgreen1069]

would not do the VST in the water if at all possible. as for parts I use baert marine, but in all honesty have never really shopped them against anybody for price, I also believe there is a very reputable yamaha supplier that has many refferals on here, SIM marine maybe???

Why wouldn't you do the VST in the water? I did my low pressure fuel pumps, VST filters, and O2 sensors while my boat was in the water. The only real concern with doing the work in the water is the possibility of losing parts. I was worried about loosing the screws, so I was extra careful.

I like SIM's for my Yamaha parts. http://www.simyamaha.com/ Their prices are usually the best (or very close), and they offer $10 shipping. Andy is very helpful and can walk you through anything you need.

 

[grady33]

Go with Andy at SIMS. He will hook you up with everything you need. Changing the fuel pumps and VST is very very easy but do it on a calm day. Just don't loose any screws. Had the same thing happen several years ago with my OX66 and it was a fuel pump. There is a small membrane that can tear. Good luck.